RED HOOK - The pilot of a single-engine French biplane replica died in a fiery crash in the final minutes of an air show at the Old Rhinebeck Aerodrome late Sunday afternoon, the Dutchess County Sheriff's Office said.

Witnesses said the pilot seemed to lose control of the plane during a mock World War I dogfight with a German triplane at about 4 p.m. Sunday. The biplane, a replica of a 1917 Nieuport 24, descended into a wooded area bounded by Stone Church and Pell roads near the town transfer station.

"The biplane broke away and nose-dived," said 43-year-old Robert Spanburgh of Saugerties, who was attending the air show with his girlfriend, Susan McDonough. "Then it disappeared behind the trees and never came back up."

The pilot's identity was being withheld by authorities pending notification of family members,

Spanburgh and McDonough described the accident as "devastating, surprising" and said a hush immediately came over the crowd as the Nieuport 24 dropped from view. The show was part of the aerodrome's 49th season.

"Everyone was really upset," said Spanburgh.

Sheriff's deputies, who blocked access to the crash site with state police, later said they discovered the burning wreckage of the plane about 1,000 feet southeast of the runway. Deputy Everett Pearsall said the plane "caught fire subsequent to the crash."

Sgt. Mark Femenella of the Dutchess County Sheriff's Office said he could not confirm whether the biplane crashed during a dogfight simulation, but he said it did occur sometime during the show and that "no other aircraft was near it - there was no midair collision or anything like that."

At the time of the accident, two Hudson Valley Men's Softball League teams were facing off at a nearby baseball field off Stone Church Road. Most observers there were unsure what exactly they saw until the group was approached by air show officials.

"I heard a large bang," said outfielder Justin Wiesenthal, 27, of Poughkeepsie. "We thought maybe something had happened, but we weren't sure because there were other (dogfight simulation-related) explosion noises."

The Rhinebeck Aerodome's Web site said the Nieuport 24 was a fast and maneuverable fighter "so admired that (it) was directly copied by the Germans."

The replica was acquired in a trade with the Aviation Heritage Center in New Zealand and was powered by a Warner 145 horsepower radial engine. It was 19 feet long, had a wingspan of 26 feet, and its maximum speed was 110 miles per hour.

The accident was the fourth at the aerodrome since 2001, but none of the others were fatal. In 2005, a pilot was injured when his biplane crashed while taking off during the air show; in 2003, a Rhinebeck Aerodrome employee suffered minor injuries when his biplane lost power and struck trees before landing. In 2001, a Long Island couple taking off from the aerodrome was injured when their plane came down in a field about 300 yards from the end of the runway.

Rhinebeck Aerodrome officials could not be reached for comment Sunday.

An investigator from the Federal Aviation Administration responded to the scene. Authorities said the investigation into the cause of the crash is ongoing.